I made some testing and it seems that starting a server from the game client fails in 2.4.12
I also tested BZFS with default, random and -world options and they did not have any issues.(Server not started from game client.)

Something I've found useful over time is to use a script to start a server up.

Here's a Batch script which works on Windows, but you will need to edit it to suit your map.

Change '[username]' with the username you use on Windows.
'mapname' will be needed to be changed to the map name you are using as well.

-Zehra

There's this game I love and it's called Ducati. ~ZehraThose who are critical of me, I'll likely be the same of them. ~ZehraThere's always something to remember and it's been a game I love. ~ZehraThe time spent is a time which can never be regained, so it's a time to enjoy. ~ZehraThe decisions we make are the ones we look forward too and the ones we regret. ~ZehraThe details and the skill of knowing and applying them is what excellence is made of. ~ZehraThe best player is the one who knows what to do and when and applies it successfully. ~ZehraThere's a difference between knowing my name and knowing me, one shows respect to my name and the other is to who I am. ~ZehraMy blog is available at zehrahblog.wordpress.com.

I'm not seeing any differing behavior between 2.4.10 and 2.4.12. We use c-ares for DNS resolution. On Windows 7, at least, and probably anything since, the 'localhost' hostname does not appear in the Windows hosts file and is instead handled special inside Window's name resolution code. Because c-ares does it's own DNS lookups (and uses the hosts file), localhost will only work if your DNS servers specifically resolve it.

The quick fix is to just use 127.0.0.1 instead of localhost.

"In addition to knowing the secrets of the Universe, I can assure you that I am also quite potty trained." -Koenma (Yu Yu Hakusho)